1. Field of the Invention
The invention relates generally to methods for planning and drilling wells.
2. Background Art
For every well drilled in a given field, the objective is to intersect a potential successful. As the number of wells in the field increases, the possibility of the well being drilled (subject well) colliding with neighboring wells (offset wells) in the field increases. Catastrophic events, which may lead to injury to and/or loss of human life, can accompany well collision. Therefore, it is imperative that the risk of well collision is minimized.
Traditionally, methods for minimizing risk of well collision involve optimizing design of the subject well such that a minimum separation distance exists between the subject well and offset wells. However, even if the subject well is designed such that a minimum separation distance exists between the subject well and the offset wells, there may still be a risk of well collision due to uncertainties in the survey data for the offset wells. Thus, a detailed and continuously updated drilling plan is needed to minimize the risk of well collision through the course of drilling the subject well.
During planning and drilling of a subject well, an anti-collision scan is run on the well design to determine if there is a risk of well collision. Risk of well collision may be expressed in terms of minimum separation distance between the subject well and offset wells. If there is a risk of well collision, a request is made for an anti-collision standard exemption. If the request is granted, then the well can be drilled according to the conditions stated in the grant. Depending on the congestion level in the field, numerous anti-collision standard exemption requests may be filed during planning and drilling of a single well.
Each processing of an anti-collision standard exemption request requires gathering of data from offset wells, followed by analysis of the data by a professional to design a safe and drillable well. The data gathering and analysis are laborious, often requiring extensive manual input, hence subject to human error. The data and analysis related to processing of anti-collision standard exemption requests for one well is typically not applied to processing of anti-collision standard exemption requests for the next well in the same field. As a result, mitigation of risk of collision of the next well is just as laborious as for the previous well.
From the foregoing, a more efficient process of mitigating risk of well collision in a field is desired.